The application relates to the technical field of projection, and discloses a projection device which can improve the brightness of projection imaging. Part of the projection device comprises: an LED light source, a color wheel, a light-equalizing rod, a convex lens, a first Fresnel lens, an LCD panel and a projection lens; a ray of target light emitted by the LED light source emits a target alternating light through the color wheel, and the target alternating light comprises five monochromatic lights including red light, green light, blue light, yellow light and white light, and the five monochromatic lights enter the light-equalizing rod for uniform treatment to emit an uniform light spot, the uniform light spot is imaged at the first Fresnel lens through the convex lens, then irradiated into the LCD panel, and projected by the projection lens.

A projection image display device of the present disclosure includes a light source, an image forming element that forms an image, a color separating and combining unit that separates first illumination light and second illumination light, and combines first projection light and second projection light reflected by the image forming element, and a notch filter that is disposed between the light source and the color separating and combining unit. A first dichroic filter reflects the first illumination light and the first projection light. A first incident angle of the first illumination light with respect to the first dichroic filter is different from a second incident angle of the first projection light with respect to the first dichroic filter. The notch filter attenuates light in a first wavelength band including a boundary between a wavelength band of the first illumination light and a wavelength band of the second illumination light.

A fluorescent plate includes a fluorescent phase which emits fluorescence by excitation light, and a plurality of voids. The plurality of voids include a plurality of particular voids having an equivalent circle diameter of 0.4 micrometers or greater and 50 micrometers or smaller. In a cross section of the fluorescent plate, the ratio of the number of the particular voids having a circularity greater than 0.6 and 1 or less to the total number of the plurality of particular voids is 50% or greater.

A lighting module is configured to provide a lighting beam and includes a light source providing an excitation beam, a rotating wheel module disposed on a transmission path of the excitation beam, and a first airflow generator. The rotating wheel module includes driving blades disposed at an interval. Any two adjacent driving blades form an airflow channel. The first airflow generator generates a first airflow that flows through the airflow channels of the driving blades to drive the rotating wheel module to rotate. At least a part of the light source is disposed on a flow path of the first airflow. With the foregoing design, the rotating wheel module can be passively rotated by the first airflow without a driver. Since a driver is omitted, the lighting module has a smaller size and greater design flexibility, and the rotating wheel module also has a larger usable area.

A wavelength conversion device includes a wavelength conversion plate, a reflective layer, a driving component and a thermal conductive layer. The wavelength conversion plate includes a lateral edge, at least one surface and a conversion region. The reflective layer is disposed on the surface of the wavelength conversion plate. The driving component is disposed near the lateral edge of the wavelength conversion plate and configured to displace the wavelength conversion plate. The thermal conductive layer is disposed on the surface of the wavelength conversion plate and thermally connected to the conversion region for conducting heat generated by the conversion region during a wavelength conversion. By disposing the thermal conductive layer on the surface of the wavelength conversion plate, the thermal conductive layer is thermally directly connected to the conversion region, so that the heat generated at the conversion region during the wavelength conversion is efficiently dissipated.

A wavelength converting includes a diffused-reflecting layer, a substrate, a photoluminescence layer, and a binder. The diffused-reflecting layer has a first surface and a second surface facing away from each other. The substrate is over the first surface of the diffused-reflecting layer. The photoluminescence layer is over the second surface of the diffused-reflecting layer. The binder is mixed at least in the photoluminescence layer or at least in the diffused-reflecting layer, the binder includes a structural unit represented by formula (1), and a characteristic absorption band in a Fourier-Transform Infrared (FTIR) Spectrum of silicon-oxygen-silicon bonds (Si—O—Si bonds) in the binder is from 900 cm.sup.−1 to 1250 cm.sup.−1, ##STR00001##
in which R represents an aromatic group.

A projector generates white light from a laser light source and uses the white light for image display. The white light generator has a rectangular light generating lens that generates excitation light of a rectangular shape from the blue light of a blue laser and a phosphor wheel, coated with a phosphor that is irradiated with the excitation light, to emit yellow light. In the phosphor wheel, a length in the vertical direction of a rectangular shape of an irradiation region is represented by v, and a length in the horizontal direction is represented by h, wherein h<v; and a center of the rectangular shape is within any one of a region having an angle of 45° or more and 135° or less and a region having an angle of 225° or more and 315° or less in the phosphor coat region of the phosphor wheel.

A wavelength conversion member includes a ceramic fluorescent body for converting a wavelength of incident light, a heat radiation member for radiating heat of the ceramic fluorescent body to an outside atmosphere, and a solder layer for joining together the ceramic fluorescent body and the heat radiation member. The solder layer includes a joining portion disposed between the ceramic fluorescent body and the heat radiation member and a protruding portion protruding outward from an outer circumferential portion of the ceramic fluorescent body. The protruding portion is spaced apart from a side surface formed on the outer circumferential portion of the ceramic fluorescent body. In the solder layer, the maximum value of thickness of the protruding portion is greater than the average value of thickness of the joining portion.

An illumination system, including a laser light source, a wavelength conversion module, and a polarization conversion unit, and a projection device are provided. A laser beam of the laser light source is converted to a wavelength conversion beam by a wavelength conversion region of the wavelength conversion module. The polarization conversion unit has multiple first polarization conversion regions and multiple second polarization conversion regions, and includes multiple phase delay sheets correspondingly located on multiple surfaces facing the laser light source and located in the second polarization conversion regions. The wavelength conversion beam with a second polarization state leaves the polarization conversion unit after passing through a surface of the polarization conversion unit in the first polarization conversion regions facing the laser light source. The wavelength conversion beam with a first polarization state leaves the polarization conversion unit after passing through the phase delay sheet in the second polarization conversion region.

An illumination system, including a light source module, a phosphor wheel, a light recycling element, and a light uniformizing element, is provided. The light source module emits an excitation light beam. The phosphor wheel includes a phosphor region. At a second timing, the other part of the excitation light beam transmitted to the phosphor region forms an unconverted light beam and is transmitted to the light recycling element, and is reflected by the light recycling element to form a recycled light beam. A part of the recycled light beam is converted into a second converted light beam. A first converted light beam and the second converted light beam are transmitted to the light uniformizing element through a same path, so that the illumination system outputs second light in the illumination light beam. A projection apparatus is also provided.